With tungsten microelectodes I plan to study the physiological properties of color-sensitive cells in the lateral geniculate nucleus and the visual cortex of the unanesthtized Rhesus monkey. Specifically, I plan to look for new classes of color-coded neurons in the geniculate and to determine their inputs by studying their afferents from the retina. I shall study simple and complex color cells in the striate cortex to see whether they are the neural basis for the McCullough effect. I shall investigate the properties of color-sensitive hypercomplex cells in the striate cortex. I will study the columnar and laminar organization of the color cells in the striate cortex, perhaps leading to a model of their synaptic arrangement. I shall try to visualize the axis-orientation columns in the monkey's cortex by autoradiography. Finally, I will investigate the color sensitivity of cells in areas 18, 19 and Zeki's V4 to learn how wavelength information is integrated beyond the striate cortex.